Pleural Effusion Overview and Practice Questions Illustration

Pleural Effusion: Overview and Practice Questions (2024)

by | Updated: May 1, 2024

A pleural effusion refers to the accumulation of excess fluid between the layers of the pleura, the thin membranes that line the lungs and the inside of the chest wall.

Often indicative of underlying medical conditions, a pleural effusion can range from being asymptomatic to causing severe respiratory distress.

Understanding its causes, diagnostic methods, and treatment options is crucial for effective patient management.

Free Access
25+ RRT Cheat Sheets and Quizzes

Get instant access to 25+ premium quizzes, mini-courses, and downloadable cheat sheets for FREE.

What is Pleural Effusion?

A pleural effusion is the accumulation of excess fluid between the layers of the pleura, the membranes lining the lungs and chest wall. This condition can result from various causes, often indicating underlying medical issues. It can lead to symptoms like shortness of breath, chest pain, and cough, requiring diagnostic evaluation and treatment.

Pleural Effusion Illustration Labeled


Pleural effusions are categorized into two primary types based on the fluid’s content and origin:

  1. Transudative: This type results from the imbalance in the production and removal of the pleural fluid due to systemic factors like heart failure or liver disease. They typically contain low protein levels.
  2. Exudative: Arising due to inflammation or damage to the pleura or nearby organs, these effusions have high protein and cellular content. Causes include infections, malignancies, and autoimmune conditions.

Note: Distinguishing between these types is crucial for accurate diagnosis and appropriate treatment.


Pleural effusions can arise from a myriad of causes, which, based on their nature, can lead to either transudative or exudative effusions:

Transudative Causes

  • Congestive Heart Failure (CHF): The most common cause, where the heart is unable to effectively pump blood, leading to fluid accumulation.
  • Cirrhosis: Advanced liver disease can lead to fluid build-up in the abdomen, which might seep into the pleural space.
  • Nephrotic Syndrome: A kidney disorder causing excessive protein loss in urine can lead to reduced oncotic pressure and fluid accumulation.
  • Atelectasis: Lung tissue collapse can occasionally lead to a transudative effusion.
  • Peritoneal Dialysis: Rarely, dialysis fluid can migrate into the pleural space.

Exudative Causes

  • Pneumonia: Bacterial, viral, or other infectious agents can cause inflammation of the pleura.
  • Malignancies: Lung cancer, breast cancer, or lymphoma can involve the pleura, leading to an effusion.
  • Tuberculosis: This infectious disease can cause a form of pleuritis, leading to fluid accumulation.
  • Pulmonary Embolism: A blood clot in the lung vessels can lead to inflammatory changes in the pleura.
  • Autoimmune Disorders: Conditions like systemic lupus erythematosus or rheumatoid arthritis can involve the pleura.
  • Pancreatitis: Inflammation of the pancreas can occasionally lead to fluid build-up in the pleural space.
  • Trauma: Chest injuries can result in blood (hemothorax) or air (pneumothorax) entering the pleural space.

Note: While this list is not exhaustive, it highlights the diverse range of conditions that can lead to a pleural effusion, underlining the importance of a comprehensive clinical assessment for correct diagnosis and treatment.


The treatment of pleural effusion primarily focuses on addressing the underlying cause and alleviating associated symptoms. 

Here’s a general overview of the treatment options:

  • Chest Tube Insertion: A flexible tube inserted between the ribs into the pleural space to remove air, blood, pus, or fluid. It helps restore proper lung function by allowing the lungs to expand fully. 
  • Observation: If the effusion is small and not causing any symptoms, it may just be monitored. The underlying cause should still be identified and treated if possible.
  • Therapeutic Thoracentesis: For larger effusions or those causing symptoms (like shortness of breath), the fluid can be removed by a procedure known as thoracentesis. This involves inserting a needle or a small tube into the pleural space and draining the fluid. Removing the fluid can provide relief from symptoms.
  • Treat the Underlying Cause: This is the most important aspect of managing pleural effusion. For instance: If the effusion is due to heart failure, then diuretics and other heart medications might be prescribed. If it’s due to infection, antibiotics will be required. In cases of malignancy, chemotherapy, radiation, or other cancer treatments might be necessary.
  • Pleurodesis: If recurrent pleural effusions are an issue, particularly in cases of malignant effusions, a procedure called pleurodesis can be considered. This involves instilling a substance (like talc) into the pleural space to cause the pleural surfaces to adhere to each other, preventing the accumulation of fluid.
  • Indwelling Pleural Catheter: For patients with recurrent malignant effusions that are not candidates for pleurodesis, a long-term indwelling pleural catheter can be placed. This allows patients or caregivers to periodically drain the fluid at home.
  • Surgery: In some cases, surgery might be necessary to address the cause of the effusion or to directly treat the effusion. For example, a procedure called a decortication can be done to remove restrictive, fibrous tissue from the pleura.
  • Diuretics: If the effusion is due to conditions like heart or kidney failure, diuretics might be prescribed to help remove excess fluid from the body.

Note: It’s important to remember that the above treatments are general overviews. The best approach for an individual will depend on their specific circumstances, including the cause of the effusion, their overall health, and other factors.

What is a Pleural Disease?

Pleural disease refers to a variety of conditions that affect the pleura, which are the thin membranes that line the outside of the lungs and the inside of the chest cavity.

The pleura is composed of two layers: the inner (visceral) layer, which is attached to the lungs, and the outer (parietal) layer, which lines the chest wall.

Between these layers is a small amount of fluid, known as pleural fluid, which lubricates the surfaces, allowing the lungs to expand and contract smoothly during breathing.

Here are some common types of pleural diseases:

  • Pleural Effusion: This is the most common pleural disorder and refers to an abnormal accumulation of fluid in the pleural space. It can result from various conditions, including heart failure, pneumonia, cancer, and pulmonary embolism.
  • Pneumothorax: This refers to the presence of air or gas in the pleural space, which can cause the lung to collapse. It can occur due to trauma, lung disease, or spontaneously without a clear cause.
  • Pleural Mesothelioma: A rare cancer that affects the pleura. It is often associated with asbestos exposure.
  • Pleurisy: Inflammation of the pleura, often due to infections. It leads to sharp chest pain that can be exacerbated by breathing.
  • Pleural Plaques: These are localized, benign areas of thickened pleura, often a result of asbestos exposure.
  • Empyema: Refers to the presence of pus in the pleural space, usually due to an infection.
  • Hemothorax: This is the accumulation of blood in the pleural space, often due to trauma or a rupture of blood vessels.

The symptoms of pleural diseases can vary but often include chest pain, cough, and shortness of breath. Diagnosis typically involves imaging studies like chest X-rays or CT scans, and sometimes procedures like thoracentesis, where a needle is inserted into the pleural space to withdraw fluid for analysis.

Treatment of pleural disease depends on the underlying cause. For instance, pleural effusions might be drained, pneumothorax might require chest tube placement, and infections may necessitate antibiotics.

Pleural Effusion Practice Questions

1. What is an abnormal accumulation of fluid in the pleural cavity?
Pleural effusion

2. What causes fluid accumulation from a pleural effusion?
The imbalance of fluid formation and absorption.

3. What are the types of pleural effusions?
Transudative and exudative

4. What happens with a transudative pleural effusion?
Increased hydrostatic pressure, decreased oncotic pressure, low protein, low specific gravity, and a low cell count.

5. What happens with an exudative pleural effusion?
Increased permeability, high protein, high specific gravity, high cell count, and increased WBCs.

6. Which type of pleural effusion causes an increased hydrostatic pressure?

7. What are the clinical features of a pleural effusion?
Pleuritic chest pain and dyspnea.

8. What physical finding varies in pleural effusions?
The amount of fluid that is present.

9. What happens to chest expansion when a pleural effusion is present?
It decreases

10. How is the percussion note for a pleural effusion?

11. What happens to fremitus when a pleural effusion is present?
It is decreased or absent.

12. How are breath sounds with a pleural effusion?
They are absent over the affected area.

13. What happens to the mediastinum when a pleural effusion is present?
There will be a mediastinal shift towards the unaffected side.

14. What is used for the diagnosis of a pleural effusion?
Chest x-ray

15. What sign on a chest x-ray helps with the diagnosis of a pleural effusion?
Blunting of the costophrenic angles

16. What type of x-ray is needed for a small pleural effusion?
Lateral decubitus

17. What are the causes of a transudative pleural effusion?
CHF, cirrhosis, and kidney disease.

18. What are the causes of an exudative pleural effusion?
Infection, neoplasms, pulmonary embolism, surgery, systemic disease, and intra-abdominal disease.

19. How can you diagnose a pleural effusion as either transudative or exudative?

20. When is pleurodesis indicated?
When the underlying disease is not treatable.

21. What additional signs and symptoms may be present with empyema?
Fever and other signs of an infection.

22. What is the respiratory therapist’s role in treating a pleural effusion?
Providing supplemental oxygen

23. Is CPT used to treat a pleural effusion?
No, CPT should not be used.

24. How to treat a pleural effusion?
The most common treatment methods for a pleural effusion are chest tube insertion and thoracentesis. However, depending on the severity of the condition, a patient may require additional treatments such as diuretic medications, antibiotic medications, or surgery.

25. What is a malignant pleural effusion?
A malignant pleural effusion is an accumulation of fluid in the pleural space that is caused by the spread of cancer.

26. What is the survival rate of those with a malignant pleural effusion?
The survival rate of those with a malignant pleural effusion depends on the type and stage of cancer.

27. A diagnosis of exudative pleural effusion would be based on what?
Pleural fluid protein/serum protein ratio > 0.5.

28. Why is a right-sided pleural effusion more common in heart failure?
The right side of the heart is responsible for pumping blood to the lungs. When this process is not working properly, fluid can leak into the pleural space.

29. What is the difference between pleurisy and pleural effusion?
Pleurisy is inflammation of the pleura, while pleural effusion is an accumulation of fluid in the pleural space.

30. What is the difference between pulmonary edema and pleural effusion?
Pulmonary edema is fluid accumulation in the air spaces of the lungs, while pleural effusion is fluid accumulation in the pleural space.

31. What is the incidence of pleural effusion in the United States?
It is estimated that 1.5 million Americans develop a pleural effusion each year.

32. What is the mortality rate of a pleural effusion in cancer patients?
Pleural effusion in cancer patients is associated with significant mortality and morbidity, with a median survival of three to twelve months.

33. Transudative pleural effusions are often caused by what?
Abnormal lung pressure

34. Exudative pleural effusions form as a result of what?
Inflammation of the pleura that is often caused by a lung disease

35. What is the difference between a hemothorax and pleural effusion?
A hemothorax is a collection of blood in the pleural space, while a pleural effusion is an accumulation of fluid in the pleural space.

36. How does a pleural effusion show up in an imaging study?
It shows up as densities with blunted costophrenic angles.

37. Which view best shows the amount of fluid in the lungs?
Lateral decubitus

38. Which lung condition most often requires treatment with a thoracentesis?
Pleural effusion

39. Which way does the trachea shift when a pleural effusion is present?
It shifts away from the affected side.

40. What other imaging technique can be used to find a pleural effusion?

41. Which type of pleural fluid is associated with CHF?

42. Which type of pleural fluid is associated with empyema?

43. What common lung infection can lead to a pleural effusion?

44. When is a dull percussion note heard?
Over areas of fluid and consolidation

45. How does the area of pleural effusion appear on a chest x-ray?
The affected area is solid and white.

46. Which way does the mediastinum shift when a pleural effusion is present?
To the unaffected side

47. Which type of pleural effusion is a radiographic sign of heart failure?
Bilateral pleural effusions

48. What commonly occurs adjacent to pleural effusions after abdominal or thoracic surgery?

49. What are the signs of long-standing heart failure on a chest x-ray?
Cardiac enlargement and bilateral pleural effusions

50. Are pleural effusions common in patients with pneumonia?
Yes, they are common in patients with bacterial pneumonia; however, they are uncommon in patients with viral or fungal pneumonia.

Final Thoughts

A pleural effusion is a significant medical concern that warrants prompt diagnosis and appropriate management.

With advancements in diagnostic techniques such as chest imaging and thoracentesis, healthcare professionals can accurately identify the underlying cause of pleural effusion and tailor treatment plans accordingly.

Early intervention can help alleviate symptoms, prevent complications, and improve the overall prognosis for individuals affected by this condition.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020.
  • Clinical Manifestations and Assessment of Respiratory Disease. 8th ed., Mosby, 2019.
  • Krishna, Rachana, and Mohan Rudrappa. “Pleural Effusion.” National Library of Medicine, 11 Aug. 2021.
  • Jany, Berthold, et al. “Pleural Effusion in Adults—Etiology, Diagnosis, and Treatment.” National Library of Medicine, Dtsch Arztebl Int, May 2019.
  • Karkhanis, Vinaya S., and Jyotsna M. Joshi. “Pleural Effusion: Diagnosis, Treatment, and Management.” National Library of Medicine, Open Access Emerg Med, 22 June 2012.

Recommended Reading